This invention relates to alternating-current (a-c) plasma display devices and, more particularly, to flat-panel plasma display devices made in solid-state form and designed for high-resolution full-color applications.
A variety of plasma devices suitable for full-color display are known in the art. In one such typical device, two glass plates each containing an array of parallel electrodes on one surface are assembled in a spaced-apart fashion such that the electrode arrays face each other and are orthogonally disposed to form an X-Y matrix of electrodes suitable for addressing specified regions in the space between the plates. An ionizable gas is contained between the plates. When a specified region of the gas is ionized, an associated phosphor area is excited to emit light of a particular color. For full color, each picture element of such a display comprises at least three phosphor areas each capable of emitting a different primary color. They may be arranged side-by-side or in a triad or four-quadrant fashion.
Several deficiencies in the design of plasma display devices as heretofore proposed have become apparent. For example, optical crosstalk in a typical full-color phosphor-containing device may be unavoidable. Also, as the area of such a device is increased, the spacers commonly utilized to maintain the precise glass-to-glass spacing are often found in practice to interfere with image resolution, gas discharge and electrode placement. Moreover, to ensure structural integrity of a display that utilizes conventional spacers, the glass plates may have to be undesirably thick as the area of the display is increased.
Additionally, the use of phosphors in a display device to achieve full-color capability is beset with a number of disadvantages. For example, phosphor materials are susceptible to bombardment damage from an ionized gas. This typically limits the lifetime of a phosphor-containing display device. Protective overcoatings for phosphors are known, but the use of such coatings usually decreases the excitation efficiency of the phosphor material, and thus reduce the luminescent emission of the phosphor.
Furthermore, to achieve advantageous high-resolution full-color plasma displays suitable to be used as TV video displays, a need exists for higher brightness and greater gray-scale capabilities than are presently available in known devices. To adequately satisfy this need, it is necessary that an a-c display device operate in a memory mode at frequencies that are considerably higher than those at which conventional a-c devices can operate.
Accordingly, efforts have been directed by workers skilled in the art aimed at trying to improve the design of plasma display devices. In particular, these efforts have been directed at trying to achieve practicable designs for high-resolution large-area devices capable of full-color display and high-speed operation. It was recognized that these efforts, if successful, could contribute significantly to lowering the cost and improving the performance of such devices.